It is a very valuable tool. It goes out and does a discovery, which is a great process of it. You could have something like a rogue DHCP server, and it will identify it, and then you can see to which switch port it is connected.
It is quite an impressive tool. I really liked it because you didn't have to install an agent on anything. It would just go out and do its discovery. For me, that's great.
You can check riverbed or our Saas solution (https://rufusforyou.com).
You have several alternatives but it depends if you need network monitoring, infra, a solution like APM.
Also if you are low on budget and depending on your platform and other things (for example SQL Server or Oracle) you can find alternatives.
You have oppmanager, you can use Wireshark, etc. If you use Linux most of the OS have built-in monitors and if you know scripting you can take the data from the Linux OS monitors.